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- Porsche 911 1978-1989 3.3L Turbo (930)
Flywheel Ring Gear
Restore dependable starting performance to your classic
Porsche 911 Turbo with this OE Match Flywheel Ring Gear. Designed for Porsche 911 turbo (930) models produced
between 1978 and 1989, this precision-engineered ring gear provides the
critical interface between the starter motor and flywheel, ensuring reliable
engine cranking and smooth engagement during every start-up.
Fits:
- Porsche 911 1978-1989 3.3L Turbo (930)
Manufactured to OE specifications, this replacement ring gear is engineered to deliver exceptional durability and precise fitment for the demanding requirements of the turbocharged air-cooled flat-six engine. Whether you're rebuilding a transmission, replacing a worn flywheel component or carrying out a full engine restoration, this OE Match ring gear helps maintain reliable starting performance and long-term drivetrain integrity.
Technical Specifications
- Number of Teeth: 135
- Internal Diameter: 230mm
- External Diameter: 280mm
Quality Precision Machined Gear Teeth for Correct Starter Engagement
What Does the Flywheel Ring Gear Do?
The flywheel ring gear is mounted around the outer edge of the flywheel and serves as the engagement point for the starter motor pinion gear.
When the ignition is activated, the starter motor extends its pinion gear into the teeth of the flywheel ring gear. The starter then rotates the flywheel, which in turn rotates the crankshaft and starts the engine.
The flywheel ring gear performs several essential functions:
- Transfers rotational force from the starter motor to the engine.
- Allows the engine to crank during start-up.
- Provides precise engagement with the starter pinion gear.
- Supports smooth and reliable engine starting.
- Helps prevent starter slippage and gear damage.
On the turbocharged Porsche 930, where higher compression and engine loads place greater demands on the starting system, proper ring gear condition is especially important.
Why Do Flywheel Ring Gears Fail?
Although manufactured from hardened steel, flywheel ring gears endure repeated mechanical stress throughout their service life. Every engine start places load on the gear teeth, eventually leading to wear and damage.
Common causes of flywheel ring gear failure include:
- Tooth wear from repeated starter engagement.
- Chipped, cracked or broken gear teeth.
- Worn starter motor pinion gears.
- Starter motor misalignment.
- Corrosion caused by moisture exposure.
- Excessive heat from clutch or flywheel issues.
- High mileage and decades of use.
Many Porsche 930 models have now accumulated decades of service, making flywheel and starter system inspections increasingly important during restoration and maintenance work.
When Should the Flywheel Ring Gear Be Replaced?
The ring gear should be inspected whenever the clutch,
transmission or engine assembly is removed. Replacement is recommended if any
of the following are found:
- Worn or rounded gear teeth.
- Broken or chipped teeth.
- Starter grinding noises.
- Intermittent starter engagement.
- Difficulty cranking the engine.
- Visible corrosion or physical damage.
- Excessive wear concentrated in specific areas of the gear.
Because replacement requires flywheel removal, many specialists recommend fitting a new ring gear during clutch replacement or major drivetrain refurbishment when access is readily available.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
93011623003
The product you are viewing cross references to these numbers
- Porsche 911 1968-1973 2.2L / 2.4L / 2.7L RS LWB (F)
- Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
- Porsche 911 1978-1983 3.0L / SC
- Porsche 911 1984-1986 3.2L
- Porsche 911 1975-1977 3.0L Turbo (930)
Flywheel Ring Gear
Restore dependable engine starting performance with this OE
Match Flywheel Ring Gear, designed for Porsche 911 models produced between 1970 and 1986. The flywheel
ring gear is a critical component of the engine starting system, providing the
engagement surface for the starter motor and allowing the engine to crank
reliably every time the ignition is activated.
Fits:
- Porsche 911 1968-1973 2.2L / 2.4L / 2.7L RS LWB (F)
- Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
- Porsche 911 1978-1983 3.0L / SC
- Porsche 911 1984-1986 3.2L
- Porsche 911 1975-1977 3.0L Turbo (930)
Manufactured to OE specifications, this replacement ring gear delivers the correct tooth profile, fitment and durability required for classic air-cooled Porsche applications. Whether you're rebuilding an engine, replacing a worn flywheel component or restoring a classic 911, fitting a new flywheel ring gear helps ensure smooth starter operation and long-term reliability.
What Does the Flywheel Ring Gear Do?
The flywheel ring gear is a hardened steel gear mounted around the outer circumference of the flywheel. Its primary purpose is to engage with the starter motor pinion gear during engine start-up.
When the ignition key is turned, the starter motor extends its pinion gear into the teeth of the flywheel ring gear. The starter then rotates the flywheel, turning the engine over until combustion begins and the engine starts.
The flywheel ring gear plays a vital role by:
- Providing a durable engagement surface for the starter motor.
- Allowing the engine to crank during start-up.
- Ensuring smooth and reliable starter operation.
- Transferring rotational force from the starter motor to the crankshaft.
- Supporting consistent engine starting performance.
Without a properly functioning ring gear, starter engagement can become unreliable or impossible.
Why Do Flywheel Ring Gears Fail?
Although manufactured from hardened steel, flywheel ring gears experience repeated mechanical loading every time the vehicle is started. Over decades of service, wear and damage can occur.
Common causes of failure include:
- Tooth wear caused by repeated starter engagement.
- Damaged or chipped gear teeth.
- Starter motor misalignment.
- Worn starter pinion gears damaging the ring gear.
- Excessive heat generated during clutch or flywheel issues.
- Corrosion caused by moisture contamination.
- General wear associated with high mileage and age.
On classic Porsche 911 models, decades of repeated engine starts can eventually lead to worn sections of the ring gear, particularly in the areas where the engine most commonly stops after shutdown.
When Should the Flywheel Ring Gear Be Replaced?
The flywheel ring gear should be inspected whenever the
engine, clutch or flywheel assembly is removed. Replacement is recommended if
you observe:
Chipped,
broken or heavily worn teeth.
Replacing a worn ring gear while the transmission or engine is already removed can prevent future starting problems and reduce labour costs.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
91111623904
The product you are viewing cross references to these numbers